module SPI_SEND(input clk_50m,
					 input rst_n,
					 input spi_start,
					 input[7:0] spi_data,
					 output reg spi_done,
					 output sck,
					 output reg cs,
					 output mosi
    );
reg load_c;
reg en_c;
reg load_a;
reg en_a;
reg load_b;
reg en_b;
wire [4:0]i;
parameter [4:0] s0 = 'b000001;
parameter [4:0] s1 = 'b000010;
parameter [4:0] s2 = 'b000100;
parameter [4:0] s3 = 'b001000;
parameter [4:0] s4 = 'b010000;
parameter [4:0] s5 = 'b100000;
reg [5:0]current_state = 'd0;
reg [5:0]next_state = 'd0;
always @(posedge clk_50m or negedge rst_n)
	if(!rst_n)
		current_state <= s0;
	else
		current_state <= next_state;
////////////////////////////
always @(*)
	case(current_state)
		s0:	begin
			if(spi_start)
				next_state = s1;
			else
				next_state = s0;
		end
		s1:	begin/////////////////////该状态加载待发送的数据
			if(i == 'd1)
				next_state = s2;
			else
				next_state = s1;
		end
		s2:	begin////////////////1,3,5,7,9,11,13,15
			if(i[0] == 1'b0)//////
				next_state = s3;
			else
				next_state = s2;
		end
		s3:	begin////////////////2,4,6,8,10,12,14,16
			if(i == 'd15)
				next_state = s4;
			else if(i[0] == 'd1)
				next_state = s2;
			else
				next_state = s3;
		end
		s4:	begin
			if(i == 'd16)
				next_state = s5;
			else
				next_state = s4;
		end
		s5:	begin
			if(i == 'd0)
				next_state = s0;
			else
				next_state = s5;
		end
		default:	next_state = s0;
	endcase
always @(*)
	case(current_state)
		s0:	begin///////////////////空闲状态
			load_c = 'd1;
			en_c = 'd0;
			load_a = 'd0;
			en_a = 'd0;
			load_b = 'd1;
			en_b = 'd0;
			spi_done = 'd0;
			cs = 'd1;
		end
		s1:	begin////////////////////加载待发送数据状态
			load_c = 'd0;
			en_c = 'd1;
			load_a = 'd1;
			en_a = 'd0;
			load_b = 'd0;
			en_b = 'd1;
			spi_done = 'd0;
			cs = 'd0;			
		end
		s2:	begin	////////////////第一个时钟沿发送数据
			load_c = 'd0;
			en_c = 'd1;
			load_a = 'd0;
			en_a = 'd1;
			load_b = 'd0;
			en_b = 'd1;
			spi_done = 'd0;
			cs = 'd0;	
		end
		s3:	begin////////////////第二个时钟沿采样数据
			load_c = 'd0;
			en_c = 'd1;
			load_a = 'd0;
			en_a = 'd0;
			load_b = 'd0;
			en_b = 'd1;
			spi_done = 'd0;
			cs = 'd0;
		end
		s4:	begin////////////////数据发送完毕
			load_c = 'd0;
			en_c = 'd1;
			load_a = 'd0;
			en_a = 'd0;
			load_b = 'd0;
			en_b = 'd0;
			spi_done = 'd0;
			cs = 'd0;			
		end
		s5:	begin
			load_c = 'd0;
			en_c = 'd0;
			load_a = 'd0;
			en_a = 'd0;
			load_b = 'd0;
			en_b = 'd0;
			spi_done = 'd1;
			cs = 'd1;	
		end
		default:	begin
			load_c = 'd1;
			en_c = 'd0;
			load_a = 'd0;
			en_a = 'd0;
			load_b = 'd1;
			en_b = 'd0;
			spi_done = 'd0;
			cs = 'd1;			
		end
	endcase
// Instantiate the module
count_num count_num (
    .clk_50m(clk_50m), 
    .load_c(load_c), 
    .en_c(en_c), 
    .count(i)
    );
// Instantiate the module
left_shifter left_shifter (
    .clk_50m(clk_50m), 
    .load_a(load_a), 
    .en_a(en_a), 
    .spi_data_in(spi_data), 
    .mosi(mosi)
    );
// Instantiate the module
sck_generate sck_generate (
    .clk_50m(clk_50m), 
    .load_b(load_b), 
    .en_b(en_b), 
    .sck(sck)
    );
endmodule